Three young men remain in custody after a teenager died near the scene of an alleged assault on a senior Garda officer.

The force's official watchdog has launched an investigation into the death of Jamie Ducey, 18, and is carrying out inquiries around the Abbeyside estate in Dungarvan in Co Waterford.

It is believed a group of four young men, aged in their teens and early 20s, were drinking and throwing bottles into a number of gardens in the neighbourhood off the Clonea Road in the early hours of the morning.

The house of an off-duty Garda superintendent was one of a number targeted and the officer went outside, identified himself and challenged the men some time before 2am.

It is alleged a bottle was thrown at him and he was hit on the back of his head.

The superintendent alerted colleagues who were on duty at the time and the young men then fled the scene, being pursued by gardai.

One line of inquiry is that the teenager may have been trying to cross a nearby river and was attempting to scale railings when he got into difficulties.

His body was later recovered from the water.

Three young men are being questioned by Garda.

The Garda Ombudsman confirmed it has launched an investigation after being contacted by the force in the early hours today.

A senior investigator is leading a team of four who are walking the scene around White Strand, Seapark, Clonea Road and Sallybrook.

A Garda Ombudsman (GSOC) spokeswoman said the case was referred to it at 1.59am under section 102 of the Garda Siochana Act.